He has been very proactive in sending emails to people.
This is a good start but I am afraid that he would need an enormous amount of luck to get a job from an unsolicited email. I'm afraid the process might need a different approach.
For example, start building a list of everyone he has ever worked with, especially those with whom he built up a good rapport. Find up to date contact details for them. This could take forever, so as soon as he has contact details ....
Get in touch and ask for 30 mins of their time. Suggest a coffee or drink. Prepare a set of questions to ask them, to tease out opportunities in (any business or organisation they know about)
Asking someone 'can I have a job' is very difficult for both the person asking and being asked.
Asking someone 'what do you see as the main problems with . What could he find to make it better. Where do you see this area going in the future (ie us if growing or contracting - either can be good. Remember for example when lots of people are being thrown out of a job, there are more calls for career counselling , tax advice etc.
Resist the temptation to ask 'how could I help ' directly but that is what he would ultimately be looking for.
Don't restrict it too much, if the person has another passion it might also lead somewhere.
Also ask is there anyone else you could suggest I should speak to. Again, not directly asking for a job, of course.
After each session he needs to analyse the results and look for opportunities. Any key ideas that emerge, do some google and real research to see who else might be offering that solution. Either with an aim to join forces or to outfit them.
He can then start to tell other people during these chats 'I understand xyz is a bit of a problem in your industry. '. The aim is to be in a position to offer to solve someone else's problem. They might even bite your hand off and ask you to do it. Or you can say 'well I could do xyz do you have any openings.
It's a very slow process but best to focus on progress as number of contacts, number of meetings and then bingo someone provides a lead.
In parallel, make contacts in other areas too local government must have lots of opportunities for finance people and I understand they all must be advertised.
All the very best and yes, do tell the DD gently. He has nothing to be ashamed of, in fact he is an ideal role model as others have pointed out. Not telling makes it sound like he is ashamed. Good luck.